


At This Hour

by shyberius



Category: Harry Potter - J. K. Rowling, The Mortal Instruments Series - Cassandra Clare
Genre: AU, Adventure, Alternate Universe, Angst, Fluff, Gryffindor, Hogwarts, Hogwarts AU, Hufflepuff, M/M, Ravenclaw, Romance, Shadowhunters - Freeform, Slytherin, The Dark Artifices - Freeform, the mortal instruments - Freeform
Language: English
Status: In-Progress
Published: 2018-02-02
Updated: 2018-03-03
Packaged: 2019-03-12 18:09:43
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 5
Words: 4,598
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13552788
Author URL: https://archiveofourown.org/users/shyberius/pseuds/shyberius
Summary: Join Clary, Jace, Alec, Isabelle, Simon and many others in their final year at Hogwarts.It's a year full of midnight duels, forbidden love, unexpected danger and elaborate magical pranks.And it's the beginning of everything.





	1. Rational, sensible, reliable

**Author's Note:**

> So this story is what I imagined would happen if the gang from The Mortal Intruments went to Hogwarts. It's their seventh year, and lots of danger and drama will follow in their wake.
> 
> I mean, lots. Watch out!

There was a kind of unspoken protocol about these parties - each house had a duty.

Slytherins got the word around - date, time, place - by spinning those webs of gossip that were so natural to them.

Ravenclaws made sure no professors got wind of it - soundproofing charms, decoys, elaborate lies.

Hufflepuffs decorated - levitating lanterns, strings of candles, colourful bunting - while making sure the younger ones stayed safe.

And Gryffindors? They brought the drinks.

Jace sauntered into the Gryffindors common room, the butterbeers he was carrying overflowing and sloshing onto his arms. "Izzy!" He spotted his sister's familiar dark hair in the throng of students. "Seen Clary?"

Isabelle shook her head, turning back to a very red-looking Simon. They were dancing, and he kept stepping on her toes.

"Huh." Jace deposited the drinks onto the nearest table dispiritedly. He'd had visions of him and Clary dancing for a while, then slipping away to his dorm to make out. Which was exactly what had happened at the last party before the summer (Slytherin common room, flexibility charms, his fingers in her hair, etc, etc).

But he hadn't seen her since the start of term feast, which totalled at least three hours. Not that he was counting.

Jace shook the thought, downed a whole butterbeer in one go, and joined the main crowd. He'd only just noticed the Veela band playing in front of the fireplace. The music was soft and sharp all at once - it seeped into one's pores.

It was so easy to lose yourself like this.

***

Alec couldn't think properly. As the party raged on without him, he sat by the window, his face pressed to the cool glass. Here, away from the main drag, only a few couples were dotted around. A Hufflepuff and a Slytherin girl talked in hushed tones a few feet away from him, the Hufflepuff twirling the Slytherin's hair in the fingers. Another student with no tie leaned against the wall, snoring softly.

It was so easy for Alec to let his mind wander.

His memory kept dragging him back to the feast - the hasty sorting, the usual rushed speeches, Headmaster Fell's authoritative voice, welcoming the new teacher for Defence against the Dark Arts. (The last one had resigned, after an unfortunate incident last year involving Jace and a rogue Patronus. They didn't talk about it.)

In that moment, time had felt stretched out. Like someone was pulling it from both ends.

Alec couldn't shake the image from his head. As Fell spoke his name, the new Professor - Professor Bane - had risen smoothly from his seat and smiled. But as he smiled, he had locked eyes with Alec; Alec could have sworn it was him, although he was just a dot in the sea of applauding faces in the hall.

Professor Bane flexed his hand, and his rings had glinted in the candlelight. His extraordinary slit-pupilled eyes had been purposefully trained on Alec for a split second, he was sure of it.

Alec shook his head, as if that could get rid of the memory and how it had made him feel. Deep down, he knew that this wasn't a rational feeling. And - he touched his new Head Boy badge - he had to be rational this year. Sensible. Reliable.

Alec jumped up suddenly, nearly walking into the two girls. The Veela band had changed their song to one which included a lot more incoherent screeching, and it was his job to reinforce the soundproofing charms.

***

"Izzy..."

Isabelle knew what this meant. When Simon's voice got all low and drawly like this, it meant he was going to ask her out again. This usually happened after a drink or three (pumpkin juice laced with firewhisky was Simon's favourite. Not that she'd noticed).

"Izzy, you don't have to say yes. Actually, you probably shouldn't. Because you're, like...Order of Merlin, first class, and I'm like...a house elf. That's how out of my league you are," Simon swayed to the music, his glasses and grin askew. "I'm rambling, aren't I?"

"Yes," Izzy clarified.

"Okay, okay..." His cheeks flushed again. "So, do you want to go to Hogsmeade with me?"

The Veela band finished thrashing their song to scattered applause. Izzy drew out her wand, thinking, turning it over delicately in her hands. She pointed it into her empty glass, which slowly filled with a swirling, seething liquid.

Looking into its depths, she picked her words carefully. "Yes." Simon's whole face lit up. He opened his mouth to speak, but Izzy held up her wand to silence him. "On one condition," she began, "you have to duel me."

A small crease appeared between Simon's eyebrows. "What?"

"You have to duel me, and if you win, then you can take me out to Hogsmeade." Izzy felt like a child, playing the sort of game a first year would play. Kiss and chase. Actually, she felt slighly giddy, and she wasn't sure if it was just the drink.

"I-" Simon's voice faltered before he regained his composure. He straightened his glasses. "When shall we duel?"

The corners of her lips lifted imperceptibly. "Wednesday. Midnight, in the astronomy tower."


	2. Technically forbidden

It was funny how inter-house parties were technically forbidden, but everyone knew when one had occurred. Alec, for one, could immediately spot the partygoers at breakfast the morning after. Bleary eyes, slouched posture, lazy smiles.

Funny.

Now that he was head boy, Alec was obliged to sit at the Ravenclaw table for meals. Which sucked, because now the only conversation he and Jace could have in the dining hall consisted of facial expressions.

Picking him out from the Gryffindor table, Alec raised his eyebrows at him. Jace did the same, his golden hair tousled in all directions. Then he held up his lesson timetable, his eyes wide and meaningful.

Alec pulled out his own, wondering what was so exciting about the new timetable - it was the same as last year, and he and Jace were in most of them together. (Except for Herbology. Jace detested the subject, refusing to take it since third year.)

But when Alec's eyes settled on his first lesson, his stomach did a strange flip.

 _Oh_.

Their first lesson was Defence against the Dark Arts. With Professor Bane - smiling, cat-eyed, ring-wearing Bane. And of course Jace would be excited - it was his favourite subject, and it was a new teacher.

Alec tried to calm down. He needed to prove to Jace - and himself, deep down - just how much he Didn't Care about this new professor. Because he didn't; not really.

He gave Jace an awkward thumbs up from his table, and returned to his breakfast, he cheeks burning.

Suddenly he wasn't so hungry anymore.

***

By the time Alec and Jace slipped into their usual seats at the back of the classroom, the rest of the class were already there, raising a chorus of chatter about the summer holidays. Simon - always the latest - found a seat beside Jace, gathering up his books clumsily. "What do you think he's going to be like?" He speculated.

Jace scowled. "Well, for starters, he's late."

And it was true: Professor Bane _was_ late, disappointingly so. Alec despairingly wondered whether he would turn up at all.

"By the way, where's Clary? Have either of you seen her?" Jace glanced at Alec and Simon in turn.

They both shook their heads. "Not since the Feast," replied Alec, a surge of grudging affection welling up in him. "Why, is she alr-"

"LADIES AND GENTLEMEN!" A booming voice sounded from nowhere. Simon nearly fell off his chair, and Jace snapped his head around with a small cry of annoyance. Around the rest of the room, there was a collective gasp.

Bane had appeared at the door leading to his office - now he was leaning against the doorframe, eyeing the students with meticulous attention. When he spoke again, his voice was lower, softer. "Witches and wizards."

Had he been at the door the whole time? It was as if he'd apparated there, but that wasn't allowed on school grounds. But Alec would later learn that Bane had a habit of turning up unnoticed - his footfall was light, and his slender frame could blend in anywhere.

The new Professor approached his desk at the front of the class, fiddling with his rings absentmindedly. "My name is Magnus Bane."

 _Magnus_... Alec thought this name suited him; it meant _the great_ , and there was decidedly an air of unspoken authority lingering about his person.

"As I have not spoken to your previous Professor," he began, still casting his gold-green gaze over the class, "I do not know what you have learned. But I was told that you are the most advanced class in seventh year, so my expectations of you..." His eyes settled on Alec for a moment longer than anyone else. "... Are high."

There was an incendiable silence. Next to Alec, Jace's mouth curved upward into an expectant smile. He knew that he was the best student in the most advanced class, and he couldn't wait to prove himself yet again.

"So," Bane spread his hands wide. "I'm going to give you the opportunity to show me what you can do. This Friday, I have cleared your timetable for the whole afternoon. You're going to meet me by the Gamekeeper's hut at one o'clock."

An excited whisper rose up like smoke. Bane raised a hand to silence the class, and continued: "The rules are simple. I will split the class into two teams with a captain; each team will establish a base in the forbidden forest. The first team will hide in the forest, and the signal will be given for the second team to route out their opponents. The objective of the first team is to get all of their members to their base without being disarmed."

"So...it's like manhunt?" One student - Maia Roberts, a Gryffindor - piped up.

Bane's face was in shadow. "I suppose so. Your work for this lesson is to revise on all of your defensive spells in preparation for the game."

"What about the teams?" Asked Jace.

"The teams, Mr Herondale, will be posted on the noticeboard outside my office tomorrow." Said Bane, his voice silky. Alec guessed that he had learned Jace's name from the rest of the staff - there was always a story being circulated about Jace, whether it was true or not.

Bane waved a hand, and the class set to work - some poring over books, some jumping out of their seats, their wands brandished, to practise counter-curses on each other.

Simon leaned over to confer with Alec and Jace. "Class manhunt, huh?"

"Not your average lesson." Admitted Jace, looking thoroughly pleased with the prospect of an afternoon off on Friday.

Alec, on the other hand, was apprehensive. "Do you really think Headmaster Fell's approved of this? It's the forbidden forest, Jace."

Jace shook his head dismissively. "They say becoming Head Boy makes one boring, but _I_ disagree," he nudged Alec playfully. "I think you've always been boring."

"Oh, shut up." Alec grinned, almost forgetting his sense of foreboding. And almost forgetting Professor Bane's glowing eyes, for a moment.

Except, not really.


	3. The shadows cowered

He lifted his head, and the shadows cowered before him. They bowed to what he had become.

His skin was so white it was almost translucent, black veins shuddering beneath, viscous blood circulating his body. Over his head he wore a cloak of shifting smoke, a cloak made of shame and bitterness and greed. Sometimes, when the light fell on him from a certain angle, you would catch a glimpse of his face, and it was awful.

His name was Sebastian Morgenstern. He had chosen that name for himself; Sebastian meant revered, and that was what he would surely be.

Sometimes memories chased him, skipping alongside him like leaves in a gale. They came unbidden: a green and white striped tie smeared with blood, a lock of red hair, a leering castle. Jonathan, having the Sorting Hat placed on his head like a crown. Jonathan, striding down long stoney corridors. Jonathan, leaving Hogwarts at last.

Then here was Sebastian - it had been two years since he'd left Hogwarts. Two years since Jonathan been heard of.

There was no more Jonathan, not anymore. All the good that had made up Jonathan had been eaten up by Sebastian, revered, powerful.

Now, within the walls of Hogwarts, a new group of wizards were being trained. They were going to be powerful, famous, golden.

One had golden hair and golden eyes, and was lethal in a duel. One had an enchanted bow and arrow, and deadly aim. One could poison you in your sleep, while making you fall in love with her. One was a strategist, his mind one step ahead of the rest.

One was Sebastian's sister.

Sebastian stepped out into the piercing daylight. They had to be stopped before they became too powerful. Powerful enough to destroy him.

And he knew where to start.

***

Defence against the Dark Arts was over, and, if Simon was reading his timetable correctly, they had Potions next. But, as soon as they'd left their first lesson, Jace pounded up the corridor in the opposite direction.

"Hey!" Yelled Alec. "Wrong way."

Jace kept walking, only throwing a brief glance over his shoulder to indicate that they should be following. "We're finding Clary."

Simon made a faint noise of protest as he and Alec jogged to catch up with him, their bags heavy on their backs. Jace whipped around, facing him with a pointed stare. "Your precious grades will do just fine without you for a _whole hour_ , Lewis. She's your best friend."

Simon disagreed with the first part, but thought the second part was fair. It was kind of weird that Clary hadn't shown up for so long. Plus, if Alec was willing to skip class to search for Clary, there must be some kind of urgency, because Simon was pretty sure that Alec hated Clary a bit.

Maybe hate was a strong word. The relationship between Alec and Clary was more of an I-hate-you-but-would-give-my-life-to-protect-you kind of thing.

So, that was how Simon, Jace and Alec, three of the most promising students at Hogwarts, flagrantly broke the school rules to find their equally promising best friend. Now that the rest of the school were in class, the corridors were empty, and their footfalls reverberated off the walls, filling the space.

Out of nowhere, Isabelle fell into step beside them. "You were going without me? You'd get yourselves killed."

"Is there really a chance of us getting killed on this trip, Izzy?" Replied Alec calmly, as if she snuck up on them all the time.

"Don't wanna risk it." She stuck her chin in the air defiantly. Although she was two years younger and miles shorter than any of them, Simon was terrified of her. The last time he'd seen her, she had been challenging him to a duel in a crimson, velvet dress.

"How did you know...?" Simon began.

Isabelle dismissed him with a small flick of the wrist. "I have a map, and I wanted to join in on the fun."

"Oh no," Jace groaned. "Not Marauder's Map 2.0."

"The very same," Isabelle confirmed, drawing a crumpled sheet of paper from her bag. Marauder's Map 2.0 had been created by Alec in Isabelle's second year, with the sole purpose on making sure she didn't get lost in the castle. Alec was _that_ sort of older brother. Now, when it had become clear that Isabelle could look after herself, the Map was a sort of joke to be passed from hand to hand. Since last year, when Simon had used it to accidentally discover that Isabelle frequently spent the night with a certain Slytherin boy, the Map had been disused.

Until now, apparently.

"So?" Said Jace, tapping the Map. They came out of the castle onto the edge of the Great Lake. "Where's Clary on there?"

Izzy's face darkened. "That's the other reason I joined you," A gust of wind came out of nowhere, wind, buffeting a spray of saltwater into their faces. "She's not on it. She hasn't been since last night."


	4. Invincible

Alec Lightwood was a lot of things. Loyal. Rational. Dangerous with an enchanted bow and arrow. But he was rarely angry. In fact, he wasn't even angry now, just extremely aggravated. Jace wondered what he was like when he was furious, seething, riled.

"Say it, Jace," he paced the length of his empty dorm. Jace had always been smart enough to access the Ravenclaw tower: a fact which Alec both resented and accepted. "Admit that you care about your pride before her safety."

"I never said that," muttered Jace, flopping down onto Alec's bed and running a hand through his hair.

"Then prove that it's not true." Alec shot back. "Tell the Headmaster that she's missing."

"That's not going to help, Alec! If this is anything to do with her brother, you know that Fell won't help anything. As soon as Sebastian knows someone's after him, he'll put his guard up."

"It could be anything. Maybe Sebastian's got nothing to do with it."

"Maybe he has."

The dorm was quiet. The only sound was the faint rhythmic knock of Alec's boot on the wooden floorboards.

After a fruitless search for signs of Clary on the school grounds, the five of them had trudged back to a peeved Professor Garroway and the promise of detention. Since then, Alec has suggested that they tell a teacher of her disappearance, and Jace had argued against this vehemently. That was what this was about: they both wanted to find Clary, but in two different ways.

Suddenly something snapped in Jace. He jumped to his feet to face Alec, his expression stormy. "Stop it. Stop this." He gestured vaguely. "Every since you got that stupid Head Boy badge, you've..." He trailed off, sitting back on the bed.

Alec's voice softened slightly. "I've what?"

"You've been acting like you're better. Like you're too important for us..." Jace avoided his gaze. "Too important for me."

Outside the tower, the rain began, steady, like gunfire in the distance. Alec sat down next to Jace. "Have I?"

"Forget it. We've got other things to worry about."

Alec almost flinched at the way Jace had said we - because, no matter how distant they felt, they'd always be we, always be a unit. "No," he said. Jace's face was unreadable. "Maybe I have been acting that way. And I'm sorry."

"It's just..." Alec carried on. "I've got a feeling that this is about more than just Clary. That maybe this isn't something that only we can solve."

"Fine," Jace finally looked at him, his eyes like embers. "Give it three days. If we don't find her by then, you can tell any teacher you like." At that, he rose to leave, shrugging on his quidditch jacket.

When Jace was at the door, he turned back. His voice was oddly quiet - he could be quiet, wise, when he wanted to be. "The whole Head Boy thing. Don't let power get to your head, Alec." Outside the tower, the storm broke - the clouds opened with a resonating crack. "Don't end up like Sebastian."

***

When a storm was brewing, there was only one place students weren't allowed.

Simon Lewis happened to be just there.

It was a stupid rule, really. Just because the astronomy tower was the highest point in the castle, the teachers were paranoid about it being struck by lightning.

Simon opened the window and leaned out, grinning as the fat raindrops soaked his skin. It was midnight, he was breaking the rules, and the girl he'd had a crush on since first year was going to join him soon. He felt invincible. _Go on, try and strike me now_ , he thought, gazing up into the inky sky. _I won't feel a thing_.

"Can you save falling out of the window for _after_ I beat you?" A smooth voice echoed behind him.

Simon turned around too fast, hitting his head on the windowsill as he ducked under it. "Isabelle," he spluttered.

"Fancied a shower?" She asked innocently.

Simon brought a hand to his hair, remembering that it was sopping wet. "Uh," he replied gracefully. Taking in the sight of Isabelle in a black silk dress was taking up all his powers of speech. It was tiring, honestly, being in her presence.

"Shall we begin?" She said calmly, drawing out her wand.

Simon held his in his hand - his wand looked so ordinary compared to hers. Wooden. Overused. Hers was made of dark rosewood, a blood red ruby set into it's ornate handle. If wands had personalities, Isabelle and hers would be the same.

He felt his face burning as they bowed to each other, and he hoped the darkness would hide it. For a moment, everything was still - it was the loaded silence that filled the air before thunder.

Isabelle raised her arm and let the first spell shoot from her wand, hitting Simon square in the chest and making him spin. Then another one - she was relentless. This time, Simon's glasses flew off and clattered to the ground somewhere beside him.

" _Accio!_ " He hissed, pushing them back onto his nose. This time, when she struck, Simon was ready. He deflected her curses with deft flicks of his wand, his feet planted firmly in a fighting stance, calculating his next move.

That was what had got Simon into the top class alongside Jace and Alec: it was strategy. Strategy was Simon's talent, and while he was average at best at duels, he had the power of tactics behind him. He knew all those muggle video games would come in handy for _something_.

This was it - Simon had planned it in his head perfectly.

 

He threw off Isabelle's " _Expelliarmus!_ ", jumped onto a desk, and used the resultant energy to throw himself out of the window of the tower.


	5. Eden

Time stood still for a moment. Then everything speeded up again, and Isabelle rushed to the empty window. "Simon?" Her heart leaped up into her throat. This was her fault, all her fault, and Clary would kill her -

"Up here!" A distinctly Simon-like voice drifted down from above. Isabelle looked up, craning her neck. Sure enough, crouching on the roof of the tower, his clothes soaked in rain, was Simon.

An ugly string of words flew out of her mouth. "What do you think you're _doing_?"

Simon grinned his familiar lopsided grin and climbed higher, out of her reach. "I'm getting a date."

"You'll get yourself killed first." Murmured Isabelle, but her words were drowned in the growing gale. Swearing again, she gained a foothold on the windowsill and hoisted herself up. For a sickening second, her feet slid on the rain-slicked roof tiles, but she managed to regain composure before she lost her balance.

Time stopped again. Below her, the mismatched lights of Hogwarts glistened. Towers rose like the heads of great beasts, fringed with heavy storm clouds.

Time sped up. She made out Simon's figure a few feet away and stumbled towards him, unsteady at first, but gaining confidence with every step. She'd beat him; the small fact that they were on the roof of the castle's highest tower in a raging storm wouldn't change that.

A small voice simmered at the surface of her mind: do you really want to win? Or will you let him defeat you?

" _Petrificus totalus_!" She cried, throwing her curse into the charged air. Simon cast it aside. Now they were in each other's range: Simon on the top of the slope, Isabelle on the edge.

They fought like this for what felt like hours, but was really only a few minutes, on the precarious edge of the roof. By this point the storm had grown into something else entirely, throwing them off course and obscuring all view of below. They were in their own clouded world, locked in a fiery battle of magic and wills.

Simon broke the pattern first, jumping over the edge and swinging back through the open window. Isabelle followed, closing it firmly, trapping the warmth in. Her dress clung to her cold, clammy skin.

Her mind raced to the most powerful spell she knew. " _Expulso!"_ She yelled, hoping that this would be the one to defeat him.

It was stronger that she expected. On the back wall of the classroom stood several bookcases, containing all manner of paraphernalia, from glowing orbs to leather-bound volumes. Simon was thrown against these shelves with the force of the spell, an expression of surprise frozen on his face. He collided with them with a bone-splintering crash, shaking the floor with the impact.

Perhaps Isabelle had gone a bit too far.

"I'm fine, I'm fine..." Simon coughed, propping himself up on one elbow with a pained look. The debris of chaos lay scattered around him - ripped pages, planks of wood, twisted astrology instruments.

Despite herself, Isabelle rushed towards him, crouching down so she could see his face. "You sure?"

"Yeah, yeah," Simon waved it off, standing up gingerly. His voice was higher-pitched than usual: a clear indication that he wasn't sure.

Just then, a single glass orb rolled slowly off it's shelf and hurtled to the ground, smashing into pieces. It was the sort of orb which contained secrets. When it broke, it's secret was released, seeping into Simon and Isabelle's minds like smoke.

_She was thinner than she was when she first arrived. Not that she'd noticed. But anyone from outside could have seen it in the sharp edge of her collarbone under her shirt and the hollowness of her eyes._

_The room that was once grand and luxurious has been ruined. If one stood in the middle of it and closed their eyes, they would be able to feel the generations passing through it. Ladies and gentlemen, waltzing across the tiled floor. Families being reunited, greeting each other beside the fireplace. Children playing, lying on their backs and gazing up at the painted ceiling._

_Now the floor was littered with debris and scorched with dark magic. The fireplace gaped like open jaws. And the ceiling no longer displayed pictures of Heaven and Eden, but told stories of corruption and jealousy._

_They both had green eyes. That was all._

_She lay on the cold, dry floor, her hair splayed out like rivers of blood._

_He towered above her, his white face glowing in triumph. This was where it started, and this was where it would end. He raised an arm behind his head, his fingers curled around his wand._

Isabelle recoiled from the thing. It was the orb - she was sure - that had given them that image. Now the illusion had ended, and it lay in glass pieces across the room.

Simon's face had drained of all colour. "Clary..." He muttered, more to himself that to anyone else.

"It couldn't be..." Isabelle trailed off herself, fumbling for the words. Somehow, Simon knew what she had meant to say,

"It is. It's him."

She scrambled to her feet, forgetting the ransacked classroom, her ruined dress, Simon still on his knees. Now all that was in her mind was the room in the vision, and the animal instinct that told her to run.

She offered her hand to Simon, who took it and hauled himself to his feet. In a moment like this, one of them was supposed to say, "What next?"

But that would have been a waste of precious time. They knew exactly what came next.

**Notes for the Chapter:**

> Thanks for reading - please leave comments to let me know what you thought of it!


End file.
